Snowflake Research Articles

Photochemical-assisted deposition of Ag nanoparticles on α-Fe2O3 snowflakes for ultra-sensitive SERS detection of nitrofurazone

Surface enhanced Raman Spectroscopy (SERS) stands as an exceptionally sensitive spectroscopic method extensively employed in various research fields, such as environmental monitoring, molecular diagnosis, food safety, and biochemistry. The study of semiconductor/noble-metal based SERS substrates has exponentially increased due to the apparent enhancement of Raman signal intensity by the synergistic utilization of electromagnetic and charge transfer mechanisms through the enhanced plasmonic and vibronic characteristics. Constructing an optimal assembly as a SERS substrate is the purpose pursued by many researchers. Herein, we present a promising semiconductor/noble-metal nanocomposite by photoreduction of silver nanoparticles (Ag NPs) on the hydrothermally synthesized hierarchical α-Fe2O3 snowflakes (SFs) through the green photoreduction technique. Various analytical characterization methods were employed to examine the physiochemical characteristics of the α-Fe2O3-SFs/Ag. The presented α-Fe2O3-SFs/Ag based SERS substrate enables ultra-sensitive detection of antibiotic nitrofurazone (NFZ) with the extremely low limit of detection of 3.12 × 10–14 M, the utmost enhancement factor of 3.08 × 1012, satisfactory uniformity and high reproducibility. The excellent SERS activity of the synthesized α-Fe2O3-SFs/Ag nanocomposite is owing to the generation of innumerable hotspots and the effective charge transfer for sublime Raman signal enhancement through the synergism of electromagnetic and charge transfer mechanisms. The α-Fe2O3-SFs/Ag based SERS substrate shows high recovery rate in the range of 89.9–98.78 % for detection of NFZ in the pond water and the fish feed solution for real-sample analysis. The proposed strategy in our study can efficiently detect trace amounts of NFZ in physiological circumstances and could contribute to the advancement of ultra-sensitive SERS based detection techniques.

Addressing the carbon and nitrogen impurity screening issue on HL-2M snowflake minus and conventional divertor using SOLPS

This paper demonstrates the benefits of the HL-2M SF (snowflake) minus divertor on power exhaust and impurity screening compared with the LSN (lower single null) conventional divertor using SOLPS 5.0 code package. In order to estimate the effectiveness of the impurity screening capability in the HL-2M SF minus divertor, we analyze the impurity transport behavior with intrinsic carbon impurities (P sol = 4 MW) and external injected nitrogen impurities (P sol = 6 MW) in the LSN and SF minus divertors. The simulation results reveal that an input power of and electron density of on the outer mid-plane can induce a nearly 80% pressure drop in the SOL (scrape-off layer) flux tube, representing the transition of the detachment regime in the SF minus divertor. For the higher power operation with P sol = 6 MW, a nitrogen gas puffing rate at is sufficient to exhaust excessive energy and facilitate detachment in the SF minus divertor. However, a higher gas puffing rate is necessary for the LSN divertor, indicating an improved power exhaust capability in the SF minus divertor. Furthermore, the maximum effective charge () in the SF minus divertor SOL region is nearly 1.45 versus 3.5 in the LSN case with P sol = 4 MW. The maximum in the SF minus divertor SOL region is below 2.4, versus 5.5 in the LSN case with the same impurity gas puffing rate when . Moreover, the impurity ions accumulate in the divertor region in the SF minus case, which demonstrates the effectiveness of the impurity screening capability in the HL-2M SF minus divertor. We find that the higher ionized state impurity ions contribute to the increase of and determine the impurity level upstream. On the one hand, the detached divertor regime has the benefit of suppressing the impurity particles ionizing to a higher ionized state. On the other hand, the ionization rate distribution and the poloidal velocity influenced by the friction and thermal forces determine the impurity transport behavior.

Modeling of dendritic solidification and numerical analysis of the phase-field approach to model complex morphologies in alloys

Dendrites are one of the most widely observed patterns in nature, and occur across a wide spectrum of physical phenomena—from snow flakes to river basins; from bacterial colonies to lungs and vascular systems; and in solidification and growth patterns in metals and crystals. The ubiquitous occurrence of these “tree-like” structures can be attributed to their excellent space-filling properties, and at times, dendritic structures also spatially manifest fractal-like distributions. As is the case with many fractal-like geometries, the complex multi-level branching structures in dendrites pose a modeling challenge, and a full resolution of dendritic structures is computationally very demanding. In the literature, extensive theoretical models of dendritic formation and evolution, essentially as extensions of the classical moving boundary Stefan problem exist. Much of this understanding is from the analysis of dendrites occurring during the solidification of metallic alloys, as this is critical for understanding microstructure evolution during metal manufacturing processes that involve solidification of a liquid melt. Motivated by the problem of modeling microstructure evolution from liquid melts of pure metals and metallic alloys during metal additive manufacturing, we developed a comprehensive numerical framework for modeling a large variety of dendritic structures that are relevant to metal solidification. In this work, we present a numerical framework encompassing the modeling of Stefan problem formulations relevant to dendritic evolution using a phase-field approach and a finite element method implementation. Using this framework, we model numerous complex dendritic morphologies that are physically relevant to the solidification of pure melts and binary alloys. The distinguishing aspects of this work are—a unified treatment of both pure metals and alloys; novel numerical error estimates of dendritic tip velocity; and the study of error convergence of the primal fields of temperature and the order parameter with respect to numerical discretization. To the best of our knowledge, this is a first of its kind study of numerical convergence of the phase-field equations of dendritic growth in a finite element method setting. Further, using this numerical framework, various types of physically relevant dendritic solidification patterns like single equiaxed, multi-equiaxed, single columnar and multi-columnar dendrites are modeled in two-dimensional and three-dimensional computational domains.

First snowflake divertor experiments in MAST-U tokamak

First snowflake (SF) divertor experiments in the MAST-U tokamak demonstrated steady-state snowflake-plus divertor configurations in 450 kA ohmic L-mode plasmas. The SF divertor configuration features a second poloidal field (PF) null in the divertor region close by or overlapping with the main X-point. The resulting low PF region and two additional divertor legs (strike points) may lead to additional power and particle flux sharing via a hypothesized convective cell, and increased plasma-wetted area and radiation. The free-boundary Grad–Shafranov equilibrium code FIESTA was used to design SF configurations with several inter-null distances and orientations. In the experiment, the SF configurations with inter-null distances 0.13–0.20 m and lasting 0.2–0.3 s were obtained. Parallel connection lengths between the midplane and the outer strike point in the SF configurations (evaluated at field lines 1–2 mm from the separatrix in the midplane) were 25–30 m, higher than in the standard divertor (20–25 m) or the Super-X divertor (25 m). Diagnostic measurements highlighted salient SF features. The infra-red video bolometer diagnostic showed that the radiated power peaking in the PF null region was not as pronounces as in the standard divertor. Divertor ion fluxes measured by target Langmuir probes showed increased ion flux in the plate region where a secondary SF strike point landed, concomitantly with the SF formation. These measurements may suggest that some particle and heat redistribution was taking place in the convective SF zone. The first SF experiments provide a basis for future SF studies in MAST-U tokamak with higher input power, improved plasma control and diagnostic measurements, to be compared with the modeling predictions of plasma convective SF mixing and lower density strike point detachment threshold. • First snowflake (SF) divertor experiments in the MAST-U tokamak demonstrated steady-state snowflake-plus divertor configurations with inter-null distances 0.13–0.20 m in 450 kA ohmic L-mode plasmas. • The free-boundary Grad–Shafranov equilibrium code FIESTA was used to design SF configurations with several inter-null distances and orientations. • Divertor geometry (i.e., parallel connection lengths, divertor flux expansion and area expansion) in the SF-plus divertor fvorably comared to the standard divertor • Divertor measurements with the infra-red video bolometer diagnostic and target Langmuir probes may suggest that some particle and heat redistribution took place in the convective SF zone.

Social Interaction Problems in the Multicultural Environment: Discrimination, Tolerance and “Snowfl ake Generation”

The article analyzes the risks of intercultural communication associated with the implementation of the principles of tolerance and positive discrimination. It is noted that significant changes have occurred in the sociocultural space — globalization, increased mobility, openness of public systems due to the democratization of developed countries — all this together affects the creation of multicultural society, including against the background of involving atypical groups and various minorities. The analysis of intolerance associated with manipulation and the «cancel culture» is carried out. Emphasized, that the ideas of equality and tolerance to other cultures and atypical individuals are designed to contribute to the harmonious development of personality and society, the smooth out of obvious and hidden social conflicts. However, excessive security can lead to social parasitivism, expressed in attitudes for dependent on the part of socially viable layers. The features of a new term for public consciousness «generation of snowflakes» are revealed, its author’s interpretation is presented — as a community of individuals characterized by a hypersensitive attitude to socially disapproved behavior associated with discrimination, and at the same time prone to intolerant behavior through bullying. It is concluded that it is advisable for overcoming various communicative barriers to develop intercultural competence as an integral personality characteristic that ensures intersubjective interaction and understanding. Empathy and the ability to find a common language with the interlocutor become an important resource that can prevent the risks of discrimination and intolence.

Modeling snowflake divertors in MAST-U Tokamak

In a snowflake (SF) divertor, two magnetic field nulls are placed close to each other, creating four strike points (SPs) compared to two in a standard X-point divertor. In preparation for MAST-U experiments, magnetic configurations with the standard and SF divertors with various locations and separation distances of the nulls were modeled using the two-dimensional multi-fluid code UEDGE with a full plasma transport model featuring charge-state-resolved sputtered carbon impurities. The complex interplay of the plasma transport and magnetic configurations was comprehensively studied using a simple model for the theoretically predicted fast plasma mixing driven by the ‘churning’ mode instability in the two-null SF region. The modeling results show that (1) all SF-plus configurations and SF-minus configuration with closely located nulls produce the same plasma parameters and heat fluxes at the same SPs; (2) SF divertors approach the outer and inner SP detachment conditions at lower upstream density w.r.t. the standard divertor; (3) heat flux profiles at primary SPs are substantially broadened and peak values are reduced in SF configurations w.r.t. SN divertors; this broadening becomes more pronounced with the fast plasma mixing increase.

Adenomatoid Odontogenic Tumor- A Rare Case Report of “Two Third Tumor”

Adenomatoid odontogenic tumor (AOT) is a rare odontogenic origin tumor that manifests as a slow-growing cystic neoplasm in the anterior maxilla, often in conjunction with an impacted tooth. AOTs are divided into three kinds based on their histology: follicular, extrafollicular, and peripheral. Because the source of the AOT is unknown, it's impossible to say whether the lining of an associated cyst reflects the cause i.e. a real dentigerous cyst, a cystic alteration within an AOT, or a separate entity. The diagnosis and treatment should be determined following a thorough clinical, radiographic, and histological investigation. The presented case is a rare occurrence of its sort due to the favorable patient's age and the AOT's site in the lower jaw. The current study reports on a case with follicular AOT in the anterior mandibular region (a rare location), with unusual histomorphology (snow flake and calcified areas) associated with impacted 43 and retained 83.

Parallel convection and E × B drifts in the TCV snowflake divertor and their effects on target heat-fluxes

Parallel convection and E × B drifts act together to redistribute heat between the strike-points in the low field side snowflake minus (LFS SF−). The cumulative heat convection from both mechanisms is enhanced near the secondary X-point and is shown to dominate over heat conduction, partly explaining why the LFS SF− distributes power more evenly than the single null (SN) or other snowflake (SF) configurations. Pressure profiles at the entrance of the divertor are strongly affected by the position of the secondary X-point and magnetic field direction indicating the importance of E × B drifts. Pressure drops of up to 50% appear between the outer-midplane (OMP) and the divertor entrance enhancing the role of parallel heat convection. The electron temperature and density profiles and the radial turbulent fluxes measured at the OMP are largely unaffected by the changes in divertor geometry, even on flux surfaces where the connection length is infinite.

Keeping

Keeping Thomas Dodson (bio) Click for larger view View full resolution Photo by Patrick Gaudin [End Page 20] It was a humbling thing, asking for help like this, needing it so badly. But removing his hat, brushing flakes of snow from brim and crown, Guy knew there was no other way. His neighbors' fields, already stripped of corn and soybeans, would soon be a single plain of snow, patches of winter rye the only green for acres. [End Page 21] Cold winds would blow freely across all that flatness, gathering strength until they reached the stand of pines at the edge of his apiary. The trees would provide a break, and he could wrap the hives in tar paper to keep out the frost, but it wouldn't be enough. His bees, what was left of them, they wouldn't survive an Iowa winter. He needed to take them west. He'd been standing on the porch of Taylor's place, weighed down with what he meant to ask, when he heard the baby crying. It wailed and wailed, a helpless thing, full to the top with need. When it finally hushed, he opened the screen and knocked. Taylor's wife answered. She had the baby with her, his head covered in wisps of fine brown hair, face pressed to her breast, sucking away. Guy coughed and looked down at his shoes. "Come in," Andrea said, unconcerned. "Taylor's out back, finishing up." He followed her inside, ducking to avoid the transom. Forty-odd years of lifting supers filled with honey, each box heavy as a newborn calf, had stooped his shoulders. But all told, work in the beeyard had done him good. He hadn't dwindled like other men his age, was still broad-backed and tall. He knew to move carefully in these old farmhouses. In the dining room, his eyes were drawn to the glass-windowed cabinet. It was built to house pickled beets and bottles of homemade jam, but Taylor's wife had stocked it with books, their spines emblazoned with words like "feminist," "gay and lesbian," "queer." He could remember a time when it would have been dangerous to have such books where people could see them. "Ain't much difference," his father had said, "between a cocksucker and a communist." "You're in your Sunday best," Andrea said. "Business in town?" She lowered herself into a chair and settled the baby on her lap. "The bank. Every once in a while, they like to bring you in, turn you upside down, see if anything falls out." She smiled politely. In truth, it was only for this visit that he'd traded his work boots for Oxfords, set aside his overalls, and retrieved his suit from the back of the closet. He'd worn it last ten years ago, at Alma's funeral. The back door clattered shut, and Taylor called from the kitchen, "Something got at one of the hives. Scat on the ground and some bees chewed and spat out." "In here," Andrea said. "Guy stopped by." "Oh, yeah?" Taylor said cheerfully. She strode into the room, wiping her hands on the front of her jeans, the cuffs still tucked into her socks. [End Page 22] She placed a hand on Andrea's shoulder, bent down and kissed the baby's head. The chair next to Andrea was stacked with papers. Taylor cleared them and sat down. "Should've phoned first," Guy said, shifting in his seat. "You're always welcome, you know that." The tips of his ears burning, he looked at his hands. These bouts of bashfulness, they sometimes happened around Taylor. She was just so—he couldn't think of a better word for it—handsome. She reminded him of James Dean in East of Eden and also, vaguely, of Milton Law, a high school classmate and the first boy he'd ever kissed. "Brought you this." Setting his hat on the table, he retrieved the package from under his arm, a square section of honeycomb in a clear plastic box. He'd selected, for his offering, a product of his strongest hive. Workers had filled each of the cells...

Modeling snowflake divertors in MAST-U tokamak using UEDGE code

In a snowflake (SF) divertor, two magnetic field nulls are placed close to each other creating four strike points (SPs) cf. two in a standard single-null (SN) divertor. In preparation to MAST-U experiments, magnetic configurations with SN and SF divertors located symmetrically at the top and at the bottom of the tokamak were modeled using a two-dimensional multi-fluid code UEDGE with a full plasma transport model featuring charge-state-resolved sputtered carbon impurities. SF configurations with various relative locations of the nulls and small null separation were considered. The complex interplay of the plasma transport and magnetic configurations was comprehensively studied using a simple model for the theoretically predicted fast plasma mixing (the “churning” mode) in the two-null SF region. The modeling results show that: 1) SF-plus and SF-minus configurations with closely located nulls produce same plasma parameters and heat fluxes at same SPs; 2) SF divertors approach the outer and inner SP detachment conditions at lower upstream density w.r.t. SN divertor; 3) heat flux profiles at primary SPs are substantially broadened and peak values are reduced in SF configurations w.r.t. SN divertor; this effect becomes more pronounced with the fast plasma mixing increase; 4) with the SF mixing, secondary SPs receive up to 10% (each) of the heat flux to the primary outer SP.

Türkiye’nin Nesli Tehlike Altına Olan Göl Soğanı (Leucojum Aestivum) Üzerine Araştırma ve Koruma Çalışmaları

Türkiye bitki genetik çeşitliliği ve özellikle de geofitler açısından özel bir konuma sahiptir. Ancak göl soğanı olarak bilinen Leucojum aestivum L. da dâhil olmak üzere birçok geofit türü genetik erozyona uğrayarak yok olma tehlikesi ile karşı karşıya kalmaktadır. Ülkemizde doğal olarak yetiştiği bilinen Leucojum cinsine ait tek tür olan L. aestivum Bolu, İstanbul, Bursa, Erzurum, Kocaeli, Konya ve Samsun illerinde yayılış göstermektedir. Nesli tehlike altında olan bu tür IUCN (International Union for the Conservation of Natural Resources) kırmızı liste kategorilerine göre Düşük Riskli (LC) sınıfında yer almaktadır. Aşırı otlatma ve bilinçsiz arazi yönetimi türün ana tehditleri arasında yer almaktadır. Beyaz çiçekleri ile estetik değeri olan Leucojum aestivum süs bitkisi olarak kullanılmasının yanında değerli bir tıbbi bitkidir. Soğanlarında bulunan çeşitli alkaloitler tıpta birçok hastalığın tedavisinde değerlendirilmektedir. Bu alkaloitler arasında galanthamine Alzheimer hastalığının tedavisinde kullanılan bir acetylcholinesterase enzim inhibitörü olması nedeniyle çok önemlidir. Bu nedenle L. aestivum habitatlarını korumak ve sürdürülebilirliğini sağlamak önem arz etmektedir. Ülkemizde L. aestivum ile ilgili vejetatif ve generatif çoğaltma çalışmalarının yanında in-vitro çoğaltma, içeriğindeki alkaloitlerin belirlenmesi ve bazı karyolojik araştırma çalışmaları yürütülmüştür. Türkiye’de L. aestivum’un ‘Doğal Çiçek Soğanlarının Doğadan Toplanması, Üretimi ve İhracatına İlişkin Yönetmelik’e göre ihracatı kotaya tabi tutulmaktadır. Ancak bunun dışında bilinen başka bir koruma çalışması bulunmamaktadır. Bu derleme, nesli tehlike altında olan ve Türkiye florasında doğal olarak bulunan, L. aestivum ile ilgili genel bilgilerin yanında türün koruma ve araştırma çalışmaları hakkında bilgi vermek ve bu türün önemine dikkat çekmek amacıyla hazırlanmıştır.

소셜 빅데이터를 이용한 한국내의 대만음식 트렌드 분석 : 블로그 텍스트 분석을 중심으로

The purpose of this study is to analyze the trend of Taiwanese food in Korea using text mining analysis among social big data for blogs of representative portal site in Korea, and analyzed annual trends from 2015 to 2019. The frequency was analyzed by the collected data set of blogs searched for 'Taiwanese food', and 'Taiwan', 'Travel', and 'Food' were maintained high frequency steadily in the first ranking group. The main attribute of Taiwanese food is 'street food in the night market' as well. Since then, food-related words such as 'famous place for visit', 'local restaurants', 'tasty' and 'recommendation' have been frequently found in the second ranking group. Specific Taiwanese food appeared, especially 'Beef noodle', 'Mango bingsu(snow flakes with syrup)', 'Bubble tea', 'Taiwanese pancake', and 'Zippie(flat fried chicken) ' were recognized as the representative Taiwanese foods in Korea. These findings are expected to be valuable information for entering the Korean food market, which emphasizes the value for money and shows preferences for snack foods or sweet desserts.

Preliminary engineering assessment of alternative magnetic divertor configurations for EU-DEMO

• The present work deals with a preliminary engineering development of alternative magnetic divertor configurations for EU-DEMO. • Parametric CAD master models for each configuration have been developed, including PF and TF coils, VV, ports and in-vessel components. • The configurations have been analyzed in terms of geometrical envelope and ports layout, considering structural and Remote Handling (RH) requirements. One of the main challenges in the roadmap to the realization of fusion energy is to develop a heat and power exhaust system able to withstand the large loads expected in the divertor of a fusion power plant. The challenge of reducing the heat load on the divertor targets is addressed, within the mission 2 ‘Heat-exhaust systems’, through the investigation of divertor configurations alternative to the standard Single Null (SN), such as the Snowflake (SF), Double Null (DN), X and Super-X (SX) divertors. This paper focuses on a preliminary engineering assessment of the alternative configurations proposed for the EU DEMO reactor. Starting from the description of the optimized plasma shape developed for each configuration, the 3D geometrical description of the Magnet System and of the main Mechanical Structures (Vacuum Vessel and in-vessel components) is presented. Based on the 3D geometry, the compatibility of the location and dimensions of ports with Remote Maintenance needs is discussed and possible design optimizations are proposed both for the Magnets system and the mechanical structures design. Finally, the various configurations are compared with regard to the engineering and feasibility aspects.

Turbulence and flows in the plasma boundary of snowflake magnetic configurations

Results of 3D, flux-driven, global, two-fluid turbulence simulations are presented for the first time in snowflake (SF) configurations, including the ideal SF, SF plus and SF minus configurations. The analysis is focused on the distribution of the heat flux along the four divertor legs in the sheath-limited regime and on the mechanisms that activate the four strike points. A steady equilibrium flow in the X-point region is found to play an important role for the activation of the four strike points, especially in the ideal SF case. Turbulent transport, observed in the region between the two separatrices for the SF minus configuration when the secondary X-point is on the low-field side, contributes to the redistribution of heat flux among the strike points.

Brain histiocytosis with precocious puberty and growth hormone deficiency at early childhood: A case report

Introduction. Langerhans Cell Histiocytosis (LCH) is a rare chronic granulomatous, usually multisystem disease of elusive etiology, with peak incidence in early childhood and slow progressing course. Isolated brain histiocytosis is a very rare condition and neurological finding does not correlate with the extent of space-occupying anatomical lesions and degenerative changes. Case report. A girl, age 2.5 years was presented with diabetes insipidus and nearly fatal full spectrum isolated brain histiocytosis. Brain magnetic resonance imaging (MRI) showed multiple nodules with perifocal edema, the most prominent in the projection of the hypothalamus/pituitary and the stalk and in the region of the pineal gland. Identical nodules were present in both caudate nucleus and putamen, left insular subcortex, both temporal lobes, tegmental area of the midbrain, central part of pons and medulla, both cerebellar hemispheres and leptomeningeal membranes. The pattern resembled snow balls and flakes. Biopsy showed positivity for vimentin, S-100, CD- 68 and CD1a markers. Treatment protocol LCH-III was not successful and a salvage treatment was refused by parents. She appeared again at the age of 7 with growth deceleration and fully developed precocious puberty. The control MRI of the brain revealed similar nodules in certain regression. Due to central precocious puberty, treatment with luteinizing hormone? releasing hormone (LH-RH) analogue was introduced. School performance was mediocre with cocktail-party effect behavior and slower speech. Conclusion. Brain histiocytosis is potentially fatal disease with chronic, variable, slowly progressive course and unpredictable responses to treatment protocols

Study on Flakes of a Steel Roller

The study of flakes is rare, but once it occurs, the material will suddenly burst, and the consequences are very serious. In this paper, the surface burst reason of a steel rolling mill backup roll was analyzed. The backup roll material meets a criterion of 86CrMoV7 ingredient, there are silver gray round and oval defects on macro fracture surface, visually there are more silver gray white fisheyes on the debris of the failure roller. Microscopic fracture morphology has obvious brittle fracture characteristics. The hydrogen of local surface area measured failure roller reaches 9×10−4 %, more than three times the allowable amount that flake no appear. Failure roll hairline cracks, or snow flakes assessed according to the standard are grade 2-3, which is a more serious flake level. The analysis results show that the flake is the main cause of the backup roll premature failure.

Real time magnetic control of the snowflake plasma configuration in the TCV tokamak

The novel plasma position and shape controller of the TCV tokamak aids in the precise control of complex configurations such as snowflake (SF) divertors. The ability of the controller design to simultaneously control the position, shape, divertor leg and X-points is extended to various SF plasma configurations. The unique feature of ordering the controlled variables from the most easily to the least easily controlled, while respecting the hardware limits on the poloidal-field coil currents, is exploited in particular to provide reliable control of SF equilibria with closely spaced X-points, approaching the exact snowflake. The off-line optimisation of the control parameters and their experimental implementation on snowflake plasma configuration is reported. The performance of the new controller is compared with the legacy TCV analogue controller for a SF plasma discharge. The new controller is successful in providing a marked improvement over the legacy TCV controller with respect to , the main parameter of interest for this study.

2D and 3D studies of the X-divertor configuration in the future upper divertor of ASDEX upgrade

Abstract ASDEX Upgrade is planning the installation of a pair of in-vessel coils in order to study alternative divertor configurations, like an X-divertor (XD) or a Snowflake (SF) in a machine with a high heating power compared to its size. Two designs for the technical realization of these coils are currently proposed, one including z-shaped joints and one with a single spiral conductor. The magnetic fields produced by these conductors intrinsically have a non-axisymmetric component. In particular in the XD configuration, where very shallow field line incidence angles occur, these 3D fields have a strong impact on the power distribution on the outer divertor plate. The 2D and 3D plasma transport is studied by the SOLPS and initial EMC3-EIRENE code simulations, respectively, in order to support the decision making processes of the engineering design. Although several aspects still require further attention, this paper gives a status report. The strong toroidal asymmetries observed in the power deposition pattern for the spiral conductor seem to be strongly reduced, when highly dissipative divertor conditions are reached. The asymmetry for the z-joint design is substantially smaller than the spiral conductor even for low-dissipative conditions.

The Snowflake Generation… what are they like?

The Snowflake Generation… what are they like?

Quantitative Analysis of Snow Particles Using a Multi-Angle Snowflake Camera in the Yeongdong Region

Quantitative Analysis of Snow Particles Using a Multi-Angle Snowflake Camera in the Yeongdong Region